Composite pullulan–dextran polysaccharide scaffold with interfacial polyelectrolyte complexation fibers: A platform with enhanced cell interaction and spatial distribution

Hydrogels are highly preferred in soft tissue engineering because they recapitulate the hydrated extracellular matrix. Naturally derived polysaccharides, like pullulan and dextran, are attractive materials with which to form hydrophilic polymeric networks due to their non-immunogenic and non-antigenic properties. However, their inherent hydrophilicity prevents adherent cell growth. In this study, we modified pullulan–dextran scaffolds with interfacial polyelectrolyte complexation (IPC) fibers to improve their ability to support adherent cell growth. We showed that the pullulan–dextran–IPC fiber composite scaffold laden with extracellular matrix protein has improved cell adhesion and proliferation compared to the plain polysaccharide scaffold. We also demonstrated the zero-order release kinetics of the biologics bovine serum albumin and vascular endothelial growth factor (VEGF) incorporated in the composite scaffold. Lastly, we showed that the VEGF released from the composite scaffold retained its capacity to stimulate endothelial cell growth. The incorporation of IPC fibers in the pullulan–dextran hydrogel scaffold improved its functionality and biological activity, thus enhancing its potential in tissue engineering applications.     

Toward Understanding Suicide Among Youths: Results From the White Mountain Apache Tribally Mandated Suicide Surveillance System, 2001�C2006

Objectives. We examined suicide and suicide attempt rates, patterns, and risk factors among White Mountain Apache youths (aged < 25 years) from 2001 to 2006 as the first phase of a community-based participatory research process to design and evaluate suicide prevention interventions.Methods. Apache paraprofessionals gathered data as part of a tribally mandated suicide surveillance system. We compared findings to other North American populations.Results. Between 2001 and 2006, 61% of Apache suicides occurred among youths younger than 25 years. Annual rates among those aged 15 to 24 years were highest: 128.5 per 100 000, 13 times the US all-races rate and 7 times the American Indian and Alaska Native rate. The annual suicide attempt incidence rate in this age group was 3.5%. The male-to-female ratio was 5:1 for suicide and approximately 1:1 for suicide attempts. Hanging was the most common suicide method, and third most common attempt method. The most frequently cited attempt precipitants were family or intimate partner conflict.Conclusions. An innovative tribal surveillance system identified high suicide and attempt rates and unique patterns and risk factors of suicidal behavior among Apache youths. Findings are guiding targeted suicide prevention programs.Suicide is the third leading cause of death among US youths aged 10 to 24 years,¹ and suicide attempts are a major source of adolescent morbidity in the United States. As behavioral scientists have increasingly recognized youths'' suicide behavior as an important and preventable public health problem, Healthy People 2010 has set specific objectives to reduce suicide and suicide attempt rates among youths. Past evidence supports the premise that youth suicide can be prevented by addressing risk factors and promoting early identification, referral, and treatment of mental and substance use disorders. However, risk factors vary across races, ethnic groups, and regions, necessitating targeted formative research and community-specific prevention approaches.²It is well-documented that American Indians and Alaska Natives have the highest rates of suicide of all US races.³ American Indian and Alaska Native (AIAN) suicides occur predominantly among youths ( < 25 years), in contrast to the US general population, in which deaths from suicide are concentrated among the elderly ( ≥ 65 years).⁴ Further, there is significant variability in suicide rates among youths across tribes and rural versus urban AIAN populations. Among the 1.3 million American Indians and Alaska Natives residing on or near rural reservation lands tracked by the Indian Health Service, the average rate of suicide per 100 000 is 20.2, with a range of 7.7 (Nashville area) to 45.9 (Alaska area).⁵ In comparison, for all 4.1 million American Indians and Alaska Natives identified by the US Census, the suicide rate is 11.7.⁶ Because urban AIAN residents compose approximately 60% of the US Census AIAN population,⁷ the lower overall census suicide rate indicates that rural reservation suicide rates are higher than urban AIAN suicide rates.To date, little reservation-specific information on suicide behavior or related risk factors exists to explain differences in rates across AIAN communities and in comparison with other US populations. Developing the means to collect and analyze local tribal data is key to discerning unique risk factors that are driving local and national disparities in suicide among AIAN youths, and to the public health mission of reducing suicide among youths across the United States and the world.There are approximately 15 500 White Mountain Apache (Apache) tribal members who reside on the 1.6 million acre Fort Apache Reservation in east-central Arizona. More than half (54%) of the tribal members are younger than 25 years, compared with approximately 35% of the US all-races population.⁸ In 2001, a cluster of suicides among youths on the Apache reservation led the Tribal Council to enact a resolution to mandate tribal members and community providers to report all suicidal behavior (ideation, attempts, and deaths) to a central data registry. The resulting surveillance system is the first of its kind, gathering data from both community-based and clinical settings.In 2004, as part of the Johns Hopkins Center for American Indian Health, we partnered with the Apaches to conduct a community-based participatory research (CBPR) project that included formalizing the mandated reporting process, transferring the registry system to an electronic format, analyzing quarterly trends, and engaging community leaders in interpreting surveillance data to inform prevention strategies. Because of the contentious history of research in tribal communities, CBPR methodologies are essential to ensuring a culturally sensitive interpretation of findings and culturally relevant interventions.⁹ A CBPR approach is particularly important in the complex area of mental health because explanatory models for cause and treatment of mental illness can vary widely across tribal and nontribal cultures.¹⁰We describe the Apache suicide behavior surveillance system, report patterns of Apache youths'' suicide and suicide attempts between 2001 and 2006, and compare those rates with those of other tribal and North American populations. We discuss the relevance of the paraprofessional-administered surveillance system and its findings to public health prevention of suicide behavior among youths.     

Culture Sensitivity in Assessing Urban Native American Parenting

Abstract Assessing urban Native American (NA) parenting remains a challenge for public health nurses. This study explored the effectiveness of using the NCATS and HOME instruments with urban NA mothers and their children. Scores for 63 sets of mothers and their children age 3 months to 3 years on the home observation for measurement of the environment (HOME) and nursing child assessment teaching scale (NCATS) instruments were compared with norms for those instruments. Scores were lower than the norms on the play and involvement subscales of the HOME, and higher than the norms on the total parent, clarity of cues, response to parent, and total child subscales of the NCATS. Analysis of responses to specific items indicated that these mothers were unlikely to structure and intervene in children's activities and likely to use nonverbal parenting techniques. Findings supported the usefulness of these instruments with NA parents when accompanied by discussion of findings with them, and nurse awareness of common family structures and traditional values.     

Convergent validity of a digital image-based food record to assess food group intake in youth

Current methods to assess the dietary behavior of youth have many limitations that reduce accuracy. Previous research has examined use of food images to assess nutrient intake. The objectives for this study are to validate the use of a novel digital image-based food record (DIFR) method to assess food group intake in youth and examine inter-analyst reliability. In 2009, a convenience sample of youth aged 9 to 12 years were recruited in Davis, CA, and asked to take images of the food they ate between 5 pm and bedtime for 7 days. To examine convergent validity, 1-day and average weekly food group intakes assessed by DIFR were compared to food group estimates derived from 24-hour dietary recalls. To examine interanalyst reliability, estimates of food group intakes made by two independent nutrition students were compared, using Spearman correlation coefficients. Data from 26 youth showed that each participant's 1-day food group intakes assessed by the DIFR and recall methods were significantly correlated (P<0.001) for both analysts for all food groups. Estimated average daily intake amounts determined by the DIFR method and recall methods were also significantly correlated for all food groups except grains (n=28). Interanalyst reliability was very good; estimates of food group intakes, provided by the two students, were significantly correlated (n=28, P<0.001). These results show great potential for use of DIFR to assess 1 day's intake of food groups, but more research is needed to determine how well the method performs in capturing usual intake and changes in intake.